grouping
~~~~~~~~

**type**: ``integer`` **default**: ``false``

This value is used internally as the ``NumberFormatter::GROUPING_USED`` value
when using PHP's ``NumberFormatter`` class. Its documentation is non-existent,
but it appears that if you set this to ``true``, numbers will be grouped with
a comma or period (depending on your locale): ``12345.123`` would display
as ``12,345.123``.
